<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Timeline - Pure CSS</title>
    <style>
        * {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
        }

        body {
            font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
            background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
            min-height: 100vh;
            padding: 50px 20px;
            overflow-x: hidden;
        }

        .container {
            max-width: 1200px;
            margin: 0 auto;
        }

        h1 {
            text-align: center;
            color: white;
            font-size: 3em;
            margin-bottom: 20px;
            text-shadow: 2px 2px 4px rgba(0,0,0,0.3);
            animation: fadeInDown 1s ease;
        }

        .subtitle {
            text-align: center;
            color: rgba(255,255,255,0.9);
            font-size: 1.2em;
            margin-bottom: 60px;
            animation: fadeInDown 1s ease 0.2s both;
        }

        .timeline {
            position: relative;
            padding: 50px 0;
        }

        /* Center line */
        .timeline::before {
            content: '';
            position: absolute;
            left: 50%;
            transform: translateX(-50%);
            width: 4px;
            height: 100%;
            background: linear-gradient(to bottom, 
                rgba(255,255,255,0.3),
                rgba(255,255,255,0.8),
                rgba(255,255,255,0.3)
            );
            animation: lineGrow 2s ease;
        }

        /* Timeline item */
        .timeline-item {
            position: relative;
            margin-bottom: 50px;
            width: 100%;
            animation: fadeIn 0.8s ease backwards;
        }

        .timeline-item:nth-child(1) { animation-delay: 0.3s; }
        .timeline-item:nth-child(2) { animation-delay: 0.5s; }
        .timeline-item:nth-child(3) { animation-delay: 0.7s; }
        .timeline-item:nth-child(4) { animation-delay: 0.9s; }
        .timeline-item:nth-child(5) { animation-delay: 1.1s; }
        .timeline-item:nth-child(6) { animation-delay: 1.3s; }

        /* Content positioning - Left and Right */
        .timeline-item:nth-child(odd) .content {
            left: 0;
            text-align: right;
            padding-right: 60px;
        }

        .timeline-item:nth-child(even) .content {
            left: 50%;
            text-align: left;
            padding-left: 60px;
        }

        .content {
            position: relative;
            width: 50%;
            padding: 30px;
            background: white;
            border-radius: 15px;
            box-shadow: 0 10px 30px rgba(0,0,0,0.3);
            transition: all 0.3s ease;
        }

        .content:hover {
            transform: scale(1.05);
            box-shadow: 0 15px 40px rgba(0,0,0,0.4);
        }

        /* Center dot */
        .timeline-item::before {
            content: '';
            position: absolute;
            left: 50%;
            transform: translateX(-50%);
            width: 20px;
            height: 20px;
            background: white;
            border: 4px solid #667eea;
            border-radius: 50%;
            z-index: 1;
            top: 30px;
            box-shadow: 0 0 0 4px rgba(255,255,255,0.3);
            animation: pulse 2s ease infinite;
        }

        /* Connector line from dot to content */
        .content::before {
            content: '';
            position: absolute;
            top: 30px;
            width: 30px;
            height: 2px;
            background: rgba(255,255,255,0.5);
        }

        .timeline-item:nth-child(odd) .content::before {
            right: 30px;
        }

        .timeline-item:nth-child(even) .content::before {
            left: 30px;
        }

        .date {
            display: inline-block;
            padding: 8px 20px;
            background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
            color: white;
            border-radius: 20px;
            font-weight: bold;
            font-size: 0.9em;
            margin-bottom: 15px;
            box-shadow: 0 4px 10px rgba(102, 126, 234, 0.3);
        }

        .content h2 {
            color: #333;
            margin-bottom: 10px;
            font-size: 1.5em;
        }

        .content p {
            color: #666;
            line-height: 1.6;
            margin-bottom: 15px;
        }

        .tag {
            display: inline-block;
            padding: 5px 12px;
            background: #f0f0f0;
            border-radius: 15px;
            font-size: 0.8em;
            color: #667eea;
            margin-right: 8px;
            margin-top: 10px;
        }

        /* Icon in content */
        .icon {
            display: inline-block;
            width: 50px;
            height: 50px;
            background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
            border-radius: 50%;
            margin-bottom: 15px;
            position: relative;
            box-shadow: 0 4px 10px rgba(102, 126, 234, 0.3);
        }

        .icon::before {
            content: '✓';
            position: absolute;
            color: white;
            font-size: 24px;
            font-weight: bold;
            top: 50%;
            left: 50%;
            transform: translate(-50%, -50%);
        }

        /* Responsive */
        @media (max-width: 768px) {
            .timeline::before {
                left: 30px;
            }

            .timeline-item::before {
                left: 30px;
            }

            .timeline-item:nth-child(odd) .content,
            .timeline-item:nth-child(even) .content {
                width: calc(100% - 80px);
                left: 80px;
                text-align: left;
                padding: 20px;
                padding-left: 20px;
            }

            .content::before {
                left: -30px !important;
            }

            h1 {
                font-size: 2em;
            }
        }

        /* Animations */
        @keyframes fadeInDown {
            from {
                opacity: 0;
                transform: translateY(-30px);
            }
            to {
                opacity: 1;
                transform: translateY(0);
            }
        }

        @keyframes fadeIn {
            from {
                opacity: 0;
                transform: translateY(30px);
            }
            to {
                opacity: 1;
                transform: translateY(0);
            }
        }

        @keyframes lineGrow {
            from {
                height: 0;
            }
            to {
                height: 100%;
            }
        }

        @keyframes pulse {
            0%, 100% {
                box-shadow: 0 0 0 4px rgba(255,255,255,0.3);
            }
            50% {
                box-shadow: 0 0 0 8px rgba(255,255,255,0.1);
            }
        }
    </style>
</head>
<body>
    <div class="container">
        <h1>Project Timeline</h1>
        <p class="subtitle">A Journey Through Development Milestones</p>

        <div class="timeline">
            <div class="timeline-item">
                <div class="content">
                    <div class="icon"></div>
                    <span class="date">January 2024</span>
                    <h2>Project Inception</h2>
                    <p>Initial concept and planning phase. Gathered requirements and assembled the core team for the project kickoff.</p>
                    <span class="tag">Planning</span>
                    <span class="tag">Research</span>
                </div>
            </div>

            <div class="timeline-item">
                <div class="content">
                    <div class="icon"></div>
                    <span class="date">March 2024</span>
                    <h2>Design Phase</h2>
                    <p>Created wireframes, mockups, and finalized the user interface design. Established design system and brand guidelines.</p>
                    <span class="tag">UI/UX</span>
                    <span class="tag">Design</span>
                </div>
            </div>

            <div class="timeline-item">
                <div class="content">
                    <div class="icon"></div>
                    <span class="date">May 2024</span>
                    <h2>Development Begins</h2>
                    <p>Started frontend and backend development. Implemented core features and established development workflows.</p>
                    <span class="tag">Coding</span>
                    <span class="tag">Testing</span>
                </div>
            </div>

            <div class="timeline-item">
                <div class="content">
                    <div class="icon"></div>
                    <span class="date">July 2024</span>
                    <h2>Beta Testing</h2>
                    <p>Launched beta version to select users. Collected feedback and fixed critical bugs based on user testing.</p>
                    <span class="tag">QA</span>
                    <span class="tag">Feedback</span>
                </div>
            </div>

            <div class="timeline-item">
                <div class="content">
                    <div class="icon"></div>
                    <span class="date">September 2024</span>
                    <h2>Product Launch</h2>
                    <p>Official public release of version 1.0. Marketing campaign launched across multiple channels.</p>
                    <span class="tag">Release</span>
                    <span class="tag">Marketing</span>
                </div>
            </div>

            <div class="timeline-item">
                <div class="content">
                    <div class="icon"></div>
                    <span class="date">October 2024</span>
                    <h2>Future Updates</h2>
                    <p>Planning next features based on user feedback. Continuous improvement and optimization ongoing.</p>
                    <span class="tag">Updates</span>
                    <span class="tag">Growth</span>
                </div>
            </div>
        </div>
    </div>
</body>
</html>